Rothmund-Thomson syndrome

Rothmund-Thomson syndrome (RTS) (OMIM#268400)Poikiloderma atrophicans and cataractRTS is an autosomal recessive genodermatosis presenting in infancy with a characteristic facial rash (poikiloderma), the diagnostic hallmark, and heterogeneous clinical features including short stature, sparse scalp hair, sparse or absent eyelashes and/or eyebrows, juvenile cataracts, skeletal abnormalities, radial ray defects, premature aging and a predisposition to osteosarcoma, a malignant tumour originating in bone.RTS was originally described in 1868 by the German ophthalmologist Rothmund who observed poikiloderma, growth retardation and rapidly progressive bilateral juvenile cataracts in 10 children in a Bavarian village [1]. In 1936, the English dermatologist Thomson reported three similar patients with "Poikiloderma congenitale" and growth retardation who displayed skeletal defects, including bilateral thumb aplasia and hypoplastic radii and ulnae, but no cataracts [2]. The eponym Rothmund-Thomson syndrome was coined by Taylor in 1957 to describe a group of patients with the above-mentioned disorders [3]. At present the rationale for such grouping awaits further knowledge on the molecular basis of the syndrome.Following the association in 1999 of a subset of RTS cases with homozygous or compound heterozygous mutations in the human helicase gene RECQL4 [4], two forms of RTS have emerged based on clinical and molecular analysis: type I RTS, characterised by poikiloderma, ectodermal dysplasia and juvenile cataracts, negative for the RECQL4-mutation scan and type II RTS, with poikiloderma, congenital bone defects and an increased risk of osteosarcoma related to deleterious RECQL4 mutations [5]. Whether RTS I and II represent distinct syndromes with overlapping clinical signs or intersecting nosological entities involving genes acting on the same pathway, remains to be assessed.RTS is a very rare disease and reliable data on its prevalence are not available. To date, approximately 3